Microsoft today proudly announced that Windows Phone 7 "Mango" has hit Release to Manufacturing (RTM) and has been handed to carriers for testing across the world, ahead of its official launch on new and old devices. Now, we're hearing murmurs that the release might actually hit developer devices before it comes from carriers, if they are developers.

Mobility Digest posted a screenshot of a tweet from Brandon Watson, which seems to give confirmation that Mango will hit devices before carriers release it, so that developers can continue to build their applications. Whilst the tweet doesn't outright say anything, and we're really reading between the lines here, the news of Mango RTM hitting developer devices lines up with everything we've heard too.

Right now, developers are able to load Windows Phone OS "Mango" trial build 7661 onto their devices to test and build applications, but they are required to revert back to a retail backup to upgrade to Mango RTM when it comes to carriers. The "gold" build of Mango is 7720.

If you are holding out for the next revision of Microsoft’s mobile OS, the end is near. Even though carriers could slow down the process, you can bet that Microsoft will be putting the pressure on the get this update out the door as soon as possible.

Windows Phone 7 OS "Mango" is expected to be available on new and retail devices in September. Mango brings over 500 new features to the platform, including IE9 with HTML5 support, mulititasking, OS-wide IM integration, Twitter + Facebook integration, and more.

Update: Winrumors reports that Cliff Simpkins on behalf of Microsoft has said ”We’re working to get devs an updated build soon. Stay tuned to the dev blog.” He also went on to tweet "Give me a day to get an official answer for folks," when questioned about developers getting the bits. Hopefully we'll have more news tomorrow!